Re: [PATCH v9 5/6] usb:cdns3 Add Cadence USB3 DRD Driver

From: Felipe Balbi
Date: Fri Jul 05 2019 - 07:55:24 EST


Hi,

Pawel Laszczak <pawell@xxxxxxxxxxx> writes:
> diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
> new file mode 100644
> index 000000000000..ddc73f1c87c5
> --- /dev/null
> +++ b/drivers/usb/cdns3/core.c
> @@ -0,0 +1,543 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Cadence USBSS DRD Driver.
> + *
> + * Copyright (C) 2018-2019 Cadence.
> + * Copyright (C) 2017-2018 NXP
> + * Copyright (C) 2019 Texas Instruments
> + *
> + * Author: Peter Chen <peter.chen@xxxxxxx>
> + * Pawel Laszczak <pawell@xxxxxxxxxxx>
> + * Roger Quadros <rogerq@xxxxxx>
> + */
> +
> +#include <linux/dma-mapping.h>
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/platform_device.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/pm_runtime.h>
> +
> +#include "gadget.h"
> +#include "core.h"
> +#include "host-export.h"
> +#include "gadget-export.h"
> +#include "drd.h"
> +#include "debug.h"
> +
> +/**
> + * cdns3_handshake - spin reading until handshake completes or fails
> + * @ptr: address of device controller register to be read
> + * @mask: bits to look at in result of read
> + * @done: value of those bits when handshake succeeds
> + * @usec: timeout in microseconds
> + *
> + * Returns negative errno, or zero on success
> + *
> + * Success happens when the "mask" bits have the specified value (hardware
> + * handshake done). There are two failure modes: "usec" have passed (major
> + * hardware flakeout), or the register reads as all-ones (hardware removed).
> + */
> +int cdns3_handshake(void __iomem *ptr, u32 mask, u32 done, int usec)
> +{
> + u32 result;
> +
> + do {
> + result = readl(ptr);
> + if (result == ~(u32)0) /* card removed */
> + return -ENODEV;
> +
> + result &= mask;
> + if (result == done)
> + return 0;
> +
> + udelay(1);
> + usec--;
> + } while (usec > 0);
> +
> + return -ETIMEDOUT;

looks like readl_poll_timeout_atomic() would handle this.

> +}
> +
> +static inline
> +struct cdns3_role_driver *cdns3_get_current_role_driver(struct cdns3 *cdns)
> +{
> + WARN_ON(cdns->role >= CDNS3_ROLE_END || !cdns->roles[cdns->role]);
> + return cdns->roles[cdns->role];
> +}
> +
> +static int cdns3_role_start(struct cdns3 *cdns, enum cdns3_roles role)
> +{
> + int ret;
> +
> + if (WARN_ON(role >= CDNS3_ROLE_END))
> + return 0;
> +
> + if (!cdns->roles[role])
> + return -ENXIO;
> +
> + if (cdns->roles[role]->state == CDNS3_ROLE_STATE_ACTIVE)
> + return 0;
> +
> + mutex_lock(&cdns->mutex);
> + cdns->role = role;
> + ret = cdns->roles[role]->start(cdns);
> + if (!ret)
> + cdns->roles[role]->state = CDNS3_ROLE_STATE_ACTIVE;
> + mutex_unlock(&cdns->mutex);
> + return ret;
> +}
> +
> +void cdns3_role_stop(struct cdns3 *cdns)

not static? Why is it so that _start() is static but _stop() is not?
Looks fishy

> +{
> + enum cdns3_roles role = cdns->role;
> +
> + if (role >= CDNS3_ROLE_END) {
> + WARN_ON(role > CDNS3_ROLE_END);
> + return;
> + }
> +
> + if (cdns->roles[role]->state == CDNS3_ROLE_STATE_INACTIVE)
> + return;
> +
> + mutex_lock(&cdns->mutex);
> + cdns->roles[role]->stop(cdns);
> + cdns->roles[role]->state = CDNS3_ROLE_STATE_INACTIVE;
> + mutex_unlock(&cdns->mutex);
> +}
> +
> +static void cdns3_exit_roles(struct cdns3 *cdns)
> +{
> + cdns3_role_stop(cdns);
> + cdns3_drd_exit(cdns);
> +}
> +
> +enum cdns3_roles cdsn3_get_real_role(struct cdns3 *cdns);
> +
> +static int cdns3_idle_role_start(struct cdns3 *cnds)
> +{ /* Hold PHY in RESET */

huh?

> + return 0;
> +}
> +
> +static void cdns3_idle_role_stop(struct cdns3 *cnds)
> +{
> + /* Program Lane swap and bring PHY out of RESET */

double huh?

> +}
> +
> +static int cdns3_idle_init(struct cdns3 *cdns)
> +{
> + struct cdns3_role_driver *rdrv;
> +
> + rdrv = devm_kzalloc(cdns->dev, sizeof(*rdrv), GFP_KERNEL);
> + if (!rdrv)
> + return -ENOMEM;
> +
> + rdrv->start = cdns3_idle_role_start;
> + rdrv->stop = cdns3_idle_role_stop;
> + rdrv->state = CDNS3_ROLE_STATE_INACTIVE;
> + rdrv->suspend = NULL;
> + rdrv->resume = NULL;
> + rdrv->name = "idle";

why don't you use the mux framework for this? This looks a bit fishy
too. Why do you have your own driver registration structure for your
driver only?

> +
> + cdns->roles[CDNS3_ROLE_IDLE] = rdrv;
> +
> + return 0;
> +}
> +
> +/**
> + * cdns3_core_init_role - initialize role of operation
> + * @cdns: Pointer to cdns3 structure
> + *
> + * Returns 0 on success otherwise negative errno
> + */
> +static int cdns3_core_init_role(struct cdns3 *cdns)
> +{
> + struct device *dev = cdns->dev;
> + enum usb_dr_mode best_dr_mode;
> + enum usb_dr_mode dr_mode;
> + int ret = 0;
> +
> + dr_mode = usb_get_dr_mode(dev);
> + cdns->role = CDNS3_ROLE_END;
> +
> + /*
> + * If driver can't read mode by means of usb_get_dr_mode function then
> + * chooses mode according with Kernel configuration. This setting
> + * can be restricted later depending on strap pin configuration.
> + */
> + if (dr_mode == USB_DR_MODE_UNKNOWN) {
> + if (IS_ENABLED(CONFIG_USB_CDNS3_HOST) &&
> + IS_ENABLED(CONFIG_USB_CDNS3_GADGET))
> + dr_mode = USB_DR_MODE_OTG;
> + else if (IS_ENABLED(CONFIG_USB_CDNS3_HOST))
> + dr_mode = USB_DR_MODE_HOST;
> + else if (IS_ENABLED(CONFIG_USB_CDNS3_GADGET))
> + dr_mode = USB_DR_MODE_PERIPHERAL;
> + }
> +
> + /*
> + * At this point cdns->dr_mode contains strap configuration.
> + * Driver try update this setting considering kernel configuration
> + */
> + best_dr_mode = cdns->dr_mode;
> +
> + ret = cdns3_idle_init(cdns);
> + if (ret)
> + return ret;
> +
> + if (dr_mode == USB_DR_MODE_OTG) {
> + best_dr_mode = cdns->dr_mode;
> + } else if (cdns->dr_mode == USB_DR_MODE_OTG) {
> + best_dr_mode = dr_mode;
> + } else if (cdns->dr_mode != dr_mode) {
> + dev_err(dev, "Incorrect DRD configuration\n");
> + return -EINVAL;
> + }
> +
> + dr_mode = best_dr_mode;
> +
> + if (dr_mode == USB_DR_MODE_OTG || dr_mode == USB_DR_MODE_HOST) {
> + ret = cdns3_host_init(cdns);
> + if (ret) {
> + dev_err(dev, "Host initialization failed with %d\n",
> + ret);
> + goto err;
> + }
> + }
> +
> + if (dr_mode == USB_DR_MODE_OTG || dr_mode == USB_DR_MODE_PERIPHERAL) {
> + ret = cdns3_gadget_init(cdns);
> + if (ret) {
> + dev_err(dev, "Device initialization failed with %d\n",
> + ret);
> + goto err;
> + }
> + }
> +
> + cdns->desired_dr_mode = dr_mode;
> + cdns->dr_mode = dr_mode;
> +
> + /*
> + * desired_dr_mode might have changed so we need to update
> + * the controller configuration"?
> + */
> + ret = cdns3_drd_update_mode(cdns);
> + if (ret)
> + goto err;
> +
> + cdns->role = cdsn3_get_real_role(cdns);
> +
> + ret = cdns3_role_start(cdns, cdns->role);
> + if (ret) {
> + dev_err(dev, "can't start %s role\n",
> + cdns3_get_current_role_driver(cdns)->name);
> + goto err;
> + }
> +
> + return ret;
> +err:
> + cdns3_exit_roles(cdns);
> + return ret;
> +}
> +
> +/**
> + * cdsn3_get_real_role - get real role of controller based on hardware settings.
> + * @cdns: Pointer to cdns3 structure
> + *
> + * Returns role
> + */
> +enum cdns3_roles cdsn3_get_real_role(struct cdns3 *cdns)
> +{
> + enum cdns3_roles role;
> + int id, vbus;
> +
> + if (cdns->current_dr_mode != USB_DR_MODE_OTG)
> + goto not_otg;
> +
> + id = cdns3_get_id(cdns);
> + vbus = cdns3_get_vbus(cdns);
> +
> + /*
> + * Role change state machine
> + * Inputs: ID, VBUS
> + * Previous state: cdns->role
> + * Next state: role
> + */
> + role = cdns->role;
> +
> + switch (role) {
> + case CDNS3_ROLE_IDLE: /* from IDLE, we can change to HOST or GADGET */
> + if (!id)
> + role = CDNS3_ROLE_HOST;
> + else if (vbus)
> + role = CDNS3_ROLE_GADGET;
> + break;
> + case CDNS3_ROLE_HOST: /* from HOST, we can only change to IDLE */
> + if (id)
> + role = CDNS3_ROLE_IDLE;
> + break;
> + case CDNS3_ROLE_GADGET: /* from GADGET, we can only change to IDLE */
> + if (!vbus)
> + role = CDNS3_ROLE_IDLE;
> + break;
> + case CDNS3_ROLE_END: /* only at initialization, move to IDLE */
> + role = CDNS3_ROLE_IDLE;
> + break;
> + }
> +
> + dev_dbg(cdns->dev, "role %d -> %d\n", cdns->role, role);
> +
> + return role;
> +
> +not_otg:
> + if (cdns3_is_host(cdns))
> + role = CDNS3_ROLE_HOST;
> + if (cdns3_is_device(cdns))
> + role = CDNS3_ROLE_GADGET;
> +
> + return role;
> +}
> +
> +/**
> + * cdns3_role_switch - work queue handler for role switch
> + *
> + * @work: work queue item structure
> + *
> + * Handles below events:
> + * - Role switch for dual-role devices
> + * - CDNS3_ROLE_GADGET <--> CDNS3_ROLE_END for peripheral-only devices
> + */
> +static void cdns3_role_switch(struct work_struct *work)
> +{
> + enum cdns3_roles role = CDNS3_ROLE_END;
> + struct cdns3_role_driver *role_drv;
> + enum cdns3_roles current_role;
> + struct cdns3 *cdns;
> + int ret = 0;
> +
> + cdns = container_of(work, struct cdns3, role_switch_wq);
> +
> + pm_runtime_get_sync(cdns->dev);
> +
> + role = cdsn3_get_real_role(cdns);
> +
> + role_drv = cdns3_get_current_role_driver(cdns);
> +
> + /* Disable current role if requested from debugfs */
> + if (cdns->debug_disable && role_drv->state == CDNS3_ROLE_STATE_ACTIVE) {
> + cdns3_role_stop(cdns);
> + goto exit;
> + }
> +
> + /* Do nothing if nothing changed */
> + if (cdns->role == role && role_drv->state == CDNS3_ROLE_STATE_ACTIVE)
> + goto exit;
> +
> + cdns3_role_stop(cdns);
> +
> + role = cdsn3_get_real_role(cdns);
> +
> + current_role = cdns->role;
> + dev_dbg(cdns->dev, "Switching role");
> +
> + ret = cdns3_role_start(cdns, role);
> + if (ret) {
> + /* Back to current role */
> + dev_err(cdns->dev, "set %d has failed, back to %d\n",
> + role, current_role);
> + ret = cdns3_role_start(cdns, current_role);
> + if (ret)
> + dev_err(cdns->dev, "back to %d failed too\n",
> + current_role);
> + }
> +exit:
> + pm_runtime_put_sync(cdns->dev);
> +}
> +
> +/**
> + * cdns3_probe - probe for cdns3 core device
> + * @pdev: Pointer to cdns3 core platform device
> + *
> + * Returns 0 on success otherwise negative errno
> + */
> +static int cdns3_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct resource *res;
> + struct cdns3 *cdns;
> + void __iomem *regs;
> + int ret;
> +
> + ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
> + if (ret) {
> + dev_err(dev, "error setting dma mask: %d\n", ret);
> + return -ENODEV;
> + }
> +
> + cdns = devm_kzalloc(dev, sizeof(*cdns), GFP_KERNEL);
> + if (!cdns)
> + return -ENOMEM;
> +
> + cdns->dev = dev;
> +
> + platform_set_drvdata(pdev, cdns);
> +
> + res = platform_get_resource_byname(pdev, IORESOURCE_IRQ, "host");
> + if (!res) {
> + dev_err(dev, "missing host IRQ\n");
> + return -ENODEV;
> + }
> +
> + cdns->xhci_res[0] = *res;
> +
> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "xhci");
> + if (!res) {
> + dev_err(dev, "couldn't get xhci resource\n");
> + return -ENXIO;
> + }
> +
> + cdns->xhci_res[1] = *res;
> +
> + cdns->dev_irq = platform_get_irq_byname(pdev, "peripheral");
> + if (cdns->dev_irq == -EPROBE_DEFER)
> + return cdns->dev_irq;
> +
> + if (cdns->dev_irq < 0)
> + dev_err(dev, "couldn't get peripheral irq\n");
> +
> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dev");
> + regs = devm_ioremap_resource(dev, res);
> + if (IS_ERR(regs)) {
> + dev_err(dev, "couldn't iomap dev resource\n");
> + return PTR_ERR(regs);
> + }
> + cdns->dev_regs = regs;
> +
> + cdns->otg_irq = platform_get_irq_byname(pdev, "otg");
> + if (cdns->otg_irq == -EPROBE_DEFER)
> + return cdns->otg_irq;
> +
> + if (cdns->otg_irq < 0) {
> + dev_err(dev, "couldn't get otg irq\n");
> + return cdns->otg_irq;
> + }
> +
> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "otg");
> + if (!res) {
> + dev_err(dev, "couldn't get otg resource\n");
> + return -ENXIO;
> + }
> +
> + cdns->otg_res = *res;
> +
> + mutex_init(&cdns->mutex);
> +
> + cdns->usb2_phy = devm_phy_optional_get(dev, "cdns3,usb2-phy");
> + if (IS_ERR(cdns->usb2_phy))
> + return PTR_ERR(cdns->usb2_phy);
> +
> + phy_init(cdns->usb2_phy);
> + ret = phy_init(cdns->usb2_phy);
> + if (ret)
> + return ret;
> +
> + cdns->usb3_phy = devm_phy_optional_get(dev, "cdns3,usb3-phy");
> + if (IS_ERR(cdns->usb3_phy))
> + return PTR_ERR(cdns->usb3_phy);
> +
> + phy_init(cdns->usb3_phy);
> + ret = phy_init(cdns->usb3_phy);
> + if (ret)
> + return ret;
> +
> + ret = phy_power_on(cdns->usb2_phy);
> + if (ret)
> + return ret;
> +
> + ret = phy_power_on(cdns->usb3_phy);
> + if (ret)
> + goto err1;
> +
> + INIT_WORK(&cdns->role_switch_wq, cdns3_role_switch);
> +
> + ret = cdns3_drd_init(cdns);
> + if (ret)
> + goto err2;
> +
> + ret = cdns3_core_init_role(cdns);
> + if (ret)
> + goto err2;
> +
> + cdns3_debugfs_init(cdns);
> + device_set_wakeup_capable(dev, true);
> + pm_runtime_set_active(dev);
> + pm_runtime_enable(dev);
> +
> + /*
> + * The controller needs less time between bus and controller suspend,
> + * and we also needs a small delay to avoid frequently entering low
> + * power mode.
> + */
> + pm_runtime_set_autosuspend_delay(dev, 20);
> + pm_runtime_mark_last_busy(dev);
> + pm_runtime_use_autosuspend(dev);
> + dev_dbg(dev, "Cadence USB3 core: probe succeed\n");
> +
> + return 0;
> +
> +err2:
> + phy_power_off(cdns->usb3_phy);
> +
> +err1:
> + phy_power_off(cdns->usb2_phy);
> + phy_exit(cdns->usb2_phy);
> + phy_exit(cdns->usb3_phy);
> +
> + return ret;
> +}
> +
> +/**
> + * cdns3_remove - unbind drd driver and clean up
> + * @pdev: Pointer to Linux platform device
> + *
> + * Returns 0 on success otherwise negative errno
> + */
> +static int cdns3_remove(struct platform_device *pdev)
> +{
> + struct cdns3 *cdns = platform_get_drvdata(pdev);
> +
> + pm_runtime_get_sync(&pdev->dev);
> + pm_runtime_disable(&pdev->dev);
> + pm_runtime_put_noidle(&pdev->dev);
> + cdns3_debugfs_exit(cdns);
> + cdns3_exit_roles(cdns);
> + phy_power_off(cdns->usb2_phy);
> + phy_power_off(cdns->usb3_phy);
> + phy_exit(cdns->usb2_phy);
> + phy_exit(cdns->usb3_phy);
> + return 0;
> +}
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id of_cdns3_match[] = {
> + { .compatible = "cdns,usb3" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, of_cdns3_match);
> +#endif
> +
> +static struct platform_driver cdns3_driver = {
> + .probe = cdns3_probe,
> + .remove = cdns3_remove,
> + .driver = {
> + .name = "cdns-usb3",
> + .of_match_table = of_match_ptr(of_cdns3_match),
> + },
> +};
> +
> +module_platform_driver(cdns3_driver);
> +
> +MODULE_ALIAS("platform:cdns3");
> +MODULE_AUTHOR("Pawel Laszczak <pawell@xxxxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("Cadence USB3 DRD Controller Driver");
> diff --git a/drivers/usb/cdns3/core.h b/drivers/usb/cdns3/core.h
> new file mode 100644
> index 000000000000..be95696ab17e
> --- /dev/null
> +++ b/drivers/usb/cdns3/core.h
> @@ -0,0 +1,121 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Cadence USBSS DRD Header File.
> + *
> + * Copyright (C) 2017-2018 NXP
> + * Copyright (C) 2018-2019 Cadence.
> + *
> + * Authors: Peter Chen <peter.chen@xxxxxxx>
> + * Pawel Laszczak <pawell@xxxxxxxxxxx>
> + */
> +#include <linux/usb/otg.h>
> +
> +#ifndef __LINUX_CDNS3_CORE_H
> +#define __LINUX_CDNS3_CORE_H
> +
> +struct cdns3;
> +enum cdns3_roles {
> + CDNS3_ROLE_IDLE = 0,
> + CDNS3_ROLE_HOST,
> + CDNS3_ROLE_GADGET,
> + CDNS3_ROLE_END,
> +};
> +
> +/**
> + * struct cdns3_role_driver - host/gadget role driver
> + * @start: start this role
> + * @stop: stop this role
> + * @suspend: suspend callback for this role
> + * @resume: resume callback for this role
> + * @irq: irq handler for this role
> + * @name: role name string (host/gadget)
> + * @state: current state
> + */
> +struct cdns3_role_driver {
> + int (*start)(struct cdns3 *cdns);
> + void (*stop)(struct cdns3 *cdns);
> + int (*suspend)(struct cdns3 *cdns, bool do_wakeup);
> + int (*resume)(struct cdns3 *cdns, bool hibernated);
> + const char *name;
> +#define CDNS3_ROLE_STATE_INACTIVE 0
> +#define CDNS3_ROLE_STATE_ACTIVE 1
> + int state;
> +};
> +
> +#define CDNS3_XHCI_RESOURCES_NUM 2
> +/**
> + * struct cdns3 - Representation of Cadence USB3 DRD controller.
> + * @dev: pointer to Cadence device struct
> + * @xhci_regs: pointer to base of xhci registers
> + * @xhci_res: the resource for xhci
> + * @dev_regs: pointer to base of dev registers
> + * @otg_res: the resource for otg
> + * @otg_v0_regs: pointer to base of v0 otg registers
> + * @otg_v1_regs: pointer to base of v1 otg registers
> + * @otg_regs: pointer to base of otg registers
> + * @otg_irq: irq number for otg controller
> + * @dev_irq: irq number for device controller
> + * @roles: array of supported roles for this controller
> + * @role: current role
> + * @host_dev: the child host device pointer for cdns3 core
> + * @gadget_dev: the child gadget device pointer for cdns3 core
> + * @usb2_phy: pointer to USB2 PHY
> + * @usb3_phy: pointer to USB3 PHY
> + * @role_switch_wq: work queue item for role switch
> + * @wakeup_int: the wakeup interrupt
> + * @mutex: the mutex for concurrent code at driver
> + * @dr_mode: supported mode of operation it can be only Host, only Device
> + * or OTG mode that allow to switch between Device and Host mode.
> + * This field based on firmware setting, kernel configuration
> + * and hardware configuration.
> + * @current_dr_mode: current mode of operation when in dual-role mode
> + * @desired_dr_mode: desired mode of operation when in dual-role mode.
> + * This value can be changed during runtime.
> + * Available options depends on dr_mode:
> + * dr_mode | desired_dr_mode and current_dr_mode
> + * ----------------------------------------------------------------
> + * USB_DR_MODE_HOST | only USB_DR_MODE_HOST
> + * USB_DR_MODE_PERIPHERAL | only USB_DR_MODE_PERIPHERAL
> + * USB_DR_MODE_OTG | USB_DR_MODE_OTG or USB_DR_MODE_HOST or
> + * | USB_DR_MODE_PERIPHERAL
> + * Desired_dr_role can be changed by means of debugfs.
> + * @root: debugfs root folder pointer
> + * @debug_disable:
> + */
> +struct cdns3 {
> + struct device *dev;
> + void __iomem *xhci_regs;
> + struct resource xhci_res[CDNS3_XHCI_RESOURCES_NUM];
> + struct cdns3_usb_regs __iomem *dev_regs;
> +
> + struct resource otg_res;
> + struct cdns3_otg_legacy_regs *otg_v0_regs;
> + struct cdns3_otg_regs *otg_v1_regs;
> + struct cdns3_otg_common_regs *otg_regs;
> +#define CDNS3_CONTROLLER_V0 0
> +#define CDNS3_CONTROLLER_V1 1
> + u32 version;
> +
> + int otg_irq;
> + int dev_irq;
> + struct cdns3_role_driver *roles[CDNS3_ROLE_END];
> + enum cdns3_roles role;
> + struct platform_device *host_dev;
> + struct cdns3_device *gadget_dev;
> + struct phy *usb2_phy;
> + struct phy *usb3_phy;
> + struct work_struct role_switch_wq;
> + int wakeup_int:1;
> + /* mutext used in workqueue*/
> + struct mutex mutex;
> + enum usb_dr_mode dr_mode;
> + enum usb_dr_mode current_dr_mode;
> + enum usb_dr_mode desired_dr_mode;
> + struct dentry *root;
> + int debug_disable:1;
> +};
> +
> +void cdns3_role_stop(struct cdns3 *cdns);
> +int cdns3_handshake(void __iomem *ptr, u32 mask, u32 done, int usec);
> +
> +#endif /* __LINUX_CDNS3_CORE_H */
> diff --git a/drivers/usb/cdns3/debug.h b/drivers/usb/cdns3/debug.h
> new file mode 100644
> index 000000000000..65c3d8a6cd62
> --- /dev/null
> +++ b/drivers/usb/cdns3/debug.h
> @@ -0,0 +1,173 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Cadence USBSS DRD Driver.
> + * Debug header file.
> + *
> + * Copyright (C) 2018-2019 Cadence.
> + *
> + * Author: Pawel Laszczak <pawell@xxxxxxxxxxx>
> + */
> +#ifndef __LINUX_CDNS3_DEBUG
> +#define __LINUX_CDNS3_DEBUG
> +
> +#include "core.h"
> +
> +static inline char *cdns3_decode_usb_irq(char *str,
> + enum usb_device_speed speed,
> + u32 usb_ists)
> +{
> + int ret;
> +
> + ret = sprintf(str, "IRQ %08x = ", usb_ists);
> +
> + if (usb_ists & (USB_ISTS_CON2I | USB_ISTS_CONI)) {
> + ret += sprintf(str + ret, "Connection %s\n",
> + usb_speed_string(speed));
> + }
> + if (usb_ists & USB_ISTS_DIS2I || usb_ists & USB_ISTS_DISI)
> + ret += sprintf(str + ret, "Disconnection ");
> + if (usb_ists & USB_ISTS_L2ENTI)
> + ret += sprintf(str + ret, "suspended ");
> + if (usb_ists & USB_ISTS_L1ENTI)
> + ret += sprintf(str + ret, "L1 enter ");
> + if (usb_ists & USB_ISTS_L1EXTI)
> + ret += sprintf(str + ret, "L1 exit ");
> + if (usb_ists & USB_ISTS_L2ENTI)
> + ret += sprintf(str + ret, "L2 enter ");
> + if (usb_ists & USB_ISTS_L2EXTI)
> + ret += sprintf(str + ret, "L2 exit ");
> + if (usb_ists & USB_ISTS_U3EXTI)
> + ret += sprintf(str + ret, "U3 exit ");
> + if (usb_ists & USB_ISTS_UWRESI)
> + ret += sprintf(str + ret, "Warm Reset ");
> + if (usb_ists & USB_ISTS_UHRESI)
> + ret += sprintf(str + ret, "Hot Reset ");
> + if (usb_ists & USB_ISTS_U2RESI)
> + ret += sprintf(str + ret, "Reset");
> +
> + return str;
> +}
> +
> +static inline char *cdns3_decode_ep_irq(char *str,
> + u32 ep_sts,
> + const char *ep_name)
> +{
> + int ret;
> +
> + ret = sprintf(str, "IRQ for %s: %08x ", ep_name, ep_sts);
> +
> + if (ep_sts & EP_STS_SETUP)
> + ret += sprintf(str + ret, "SETUP ");
> + if (ep_sts & EP_STS_IOC)
> + ret += sprintf(str + ret, "IOC ");
> + if (ep_sts & EP_STS_ISP)
> + ret += sprintf(str + ret, "ISP ");
> + if (ep_sts & EP_STS_DESCMIS)
> + ret += sprintf(str + ret, "DESCMIS ");
> + if (ep_sts & EP_STS_STREAMR)
> + ret += sprintf(str + ret, "STREAMR ");
> + if (ep_sts & EP_STS_MD_EXIT)
> + ret += sprintf(str + ret, "MD_EXIT ");
> + if (ep_sts & EP_STS_TRBERR)
> + ret += sprintf(str + ret, "TRBERR ");
> + if (ep_sts & EP_STS_NRDY)
> + ret += sprintf(str + ret, "NRDY ");
> + if (ep_sts & EP_STS_PRIME)
> + ret += sprintf(str + ret, "PRIME ");
> + if (ep_sts & EP_STS_SIDERR)
> + ret += sprintf(str + ret, "SIDERRT ");
> + if (ep_sts & EP_STS_OUTSMM)
> + ret += sprintf(str + ret, "OUTSMM ");
> + if (ep_sts & EP_STS_ISOERR)
> + ret += sprintf(str + ret, "ISOERR ");
> + if (ep_sts & EP_STS_IOT)
> + ret += sprintf(str + ret, "IOT ");
> +
> + return str;
> +}
> +
> +static inline char *cdns3_decode_epx_irq(char *str,
> + char *ep_name,
> + u32 ep_sts)
> +{
> + return cdns3_decode_ep_irq(str, ep_sts, ep_name);
> +}
> +
> +static inline char *cdns3_decode_ep0_irq(char *str,
> + int dir,
> + u32 ep_sts)
> +{
> + return cdns3_decode_ep_irq(str, ep_sts,
> + dir ? "ep0IN" : "ep0OUT");
> +}
> +
> +/**
> + * Debug a transfer ring.
> + *
> + * Prints out all TRBs in the endpoint ring, even those after the Link TRB.
> + *.
> + */
> +static inline char *cdns3_dbg_ring(struct cdns3_endpoint *priv_ep,
> + struct cdns3_trb *ring, char *str)
> +{
> + dma_addr_t addr = priv_ep->trb_pool_dma;
> + struct cdns3_trb *trb;
> + int trb_per_sector;
> + int ret = 0;
> + int i;
> +
> + trb_per_sector = GET_TRBS_PER_SEGMENT(priv_ep->type);
> +
> + trb = &priv_ep->trb_pool[priv_ep->dequeue];
> + ret += sprintf(str + ret, "\n\t\tRing contents for %s:", priv_ep->name);
> +
> + ret += sprintf(str + ret,
> + "\n\t\tRing deq index: %d, trb: %p (virt), 0x%llx (dma)\n",
> + priv_ep->dequeue, trb,
> + (unsigned long long)cdns3_trb_virt_to_dma(priv_ep, trb));
> +
> + trb = &priv_ep->trb_pool[priv_ep->enqueue];
> + ret += sprintf(str + ret,
> + "\t\tRing enq index: %d, trb: %p (virt), 0x%llx (dma)\n",
> + priv_ep->enqueue, trb,
> + (unsigned long long)cdns3_trb_virt_to_dma(priv_ep, trb));
> +
> + ret += sprintf(str + ret,
> + "\t\tfree trbs: %d, CCS=%d, PCS=%d\n",
> + priv_ep->free_trbs, priv_ep->ccs, priv_ep->pcs);
> +
> + if (trb_per_sector > TRBS_PER_SEGMENT)
> + trb_per_sector = TRBS_PER_SEGMENT;
> +
> + if (trb_per_sector > TRBS_PER_SEGMENT) {
> + sprintf(str + ret, "\t\tTo big transfer ring %d\n",
> + trb_per_sector);
> + return str;
> + }
> +
> + for (i = 0; i < trb_per_sector; ++i) {
> + trb = &ring[i];
> + ret += sprintf(str + ret,
> + "\t\t@%pad %08x %08x %08x\n", &addr,
> + le32_to_cpu(trb->buffer),
> + le32_to_cpu(trb->length),
> + le32_to_cpu(trb->control));
> + addr += sizeof(*trb);
> + }
> +
> + return str;
> +}
> +
> +void cdns3_dbg(struct cdns3_device *priv_dev, const char *fmt, ...);
> +
> +#ifdef CONFIG_DEBUG_FS
> +void cdns3_debugfs_init(struct cdns3 *cdns);
> +void cdns3_debugfs_exit(struct cdns3 *cdns);
> +#else
> +void cdns3_debugfs_init(struct cdns3 *cdns);
> +{ }
> +void cdns3_debugfs_exit(struct cdns3 *cdns);
> +{ }
> +#endif
> +
> +#endif /*__LINUX_CDNS3_DEBUG*/
> diff --git a/drivers/usb/cdns3/debugfs.c b/drivers/usb/cdns3/debugfs.c
> new file mode 100644
> index 000000000000..44ee78a10eb8
> --- /dev/null
> +++ b/drivers/usb/cdns3/debugfs.c
> @@ -0,0 +1,153 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Cadence USBSS DRD Controller DebugFS filer.
> + *
> + * Copyright (C) 2018-2019 Cadence.
> + *
> + * Author: Pawel Laszczak <pawell@xxxxxxxxxxx>
> + */
> +
> +#include <linux/types.h>
> +#include <linux/debugfs.h>
> +#include <linux/seq_file.h>
> +#include <linux/uaccess.h>
> +
> +#include "core.h"
> +#include "gadget.h"
> +#include "drd.h"
> +
> +static const char *const cdns3_mode[] = {
> + [USB_DR_MODE_UNKNOWN] = "unknown",
> + [USB_DR_MODE_OTG] = "otg",
> + [USB_DR_MODE_HOST] = "host",
> + [USB_DR_MODE_PERIPHERAL] = "device",
> +};

don't we have a generic version of this under usb/common ?

> +static int cdns3_mode_show(struct seq_file *s, void *unused)
> +{
> + struct cdns3 *cdns = s->private;
> +
> + seq_puts(s, cdns3_mode[cdns->current_dr_mode]);
> +
> + return 0;
> +}
> +
> +static int cdns3_mode_open(struct inode *inode, struct file *file)
> +{
> + return single_open(file, cdns3_mode_show, inode->i_private);
> +}
> +
> +static ssize_t cdns3_mode_write(struct file *file,
> + const char __user *ubuf,
> + size_t count, loff_t *ppos)
> +{
> + struct seq_file *s = file->private_data;
> + struct cdns3 *cdns = s->private;
> + char buf[32];
> + int ret;
> +
> + if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
> + return -EFAULT;
> +
> + if (cdns->debug_disable) {
> + dev_err(cdns->dev,
> + "Mode can't be changed when disable is set\n");
> + return -EPERM;
> + }
> +
> + ret = match_string(cdns3_mode, ARRAY_SIZE(cdns3_mode), buf);
> + if (ret < 0 || ret == USB_DR_MODE_UNKNOWN) {
> + dev_err(cdns->dev, "Failed: incorrect mode setting\n");
> + return -EINVAL;
> + }
> +
> + if (cdns->current_dr_mode != ret) {
> + cdns->desired_dr_mode = ret;
> + cdns3_role_stop(cdns);
> + ret = cdns3_drd_update_mode(cdns);
> + if (ret)
> + return ret;
> +
> + queue_work(system_freezable_wq, &cdns->role_switch_wq);
> + }
> +
> + return count;
> +}
> +
> +static const struct file_operations cdns3_mode_fops = {
> + .open = cdns3_mode_open,
> + .write = cdns3_mode_write,
> + .read = seq_read,
> + .llseek = seq_lseek,
> + .release = single_release,
> +};
> +
> +static int cdns3_disable_show(struct seq_file *s, void *unused)
> +{
> + struct cdns3 *cdns = s->private;
> +
> + if (!cdns->debug_disable)
> + seq_puts(s, "0\n");
> + else
> + seq_puts(s, "1\n");
> +
> + return 0;
> +}
> +
> +static ssize_t cdns3_disable_write(struct file *file,
> + const char __user *ubuf,
> + size_t count, loff_t *ppos)
> +{
> + struct seq_file *s = file->private_data;
> + struct cdns3 *cdns = s->private;
> + bool disable;
> + char buf[16];
> +
> + if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
> + return -EFAULT;
> +
> + if (kstrtobool(buf, &disable)) {
> + dev_err(cdns->dev, "wrong setting\n");
> + return -EINVAL;
> + }
> +
> + if (disable != cdns->debug_disable) {
> + cdns->debug_disable = disable;
> + queue_work(system_freezable_wq, &cdns->role_switch_wq);
> + }
> +
> + return count;
> +}
> +
> +static int cdns3_disable_open(struct inode *inode, struct file *file)
> +{
> + return single_open(file, cdns3_disable_show, inode->i_private);
> +}
> +
> +static const struct file_operations cdns3_disable_fops = {
> + .open = cdns3_disable_open,
> + .write = cdns3_disable_write,
> + .read = seq_read,
> + .llseek = seq_lseek,
> + .release = single_release,
> +};
> +
> +void cdns3_debugfs_init(struct cdns3 *cdns)
> +{
> + struct dentry *root;
> +
> + root = debugfs_create_dir(dev_name(cdns->dev), NULL);

put this under usb root. I should move dwc3 there too.

> + cdns->root = root;
> + if (IS_ENABLED(CONFIG_USB_CDNS3_GADGET) &&
> + IS_ENABLED(CONFIG_USB_CDNS3_HOST))
> + debugfs_create_file("mode", 0644, root, cdns,
> + &cdns3_mode_fops);
> +
> + debugfs_create_file("disable", 0644, root, cdns,
> + &cdns3_disable_fops);
> +}
> +
> +void cdns3_debugfs_exit(struct cdns3 *cdns)
> +{
> + debugfs_remove_recursive(cdns->root);
> +}
> diff --git a/drivers/usb/cdns3/drd.c b/drivers/usb/cdns3/drd.c
> new file mode 100644
> index 000000000000..b06929fe1175
> --- /dev/null
> +++ b/drivers/usb/cdns3/drd.c
> @@ -0,0 +1,379 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Cadence USBSS DRD Driver.
> + *
> + * Copyright (C) 2018-2019 Cadence.
> + * Copyright (C) 2019 Texas Instruments
> + *
> + * Author: Pawel Laszczak <pawell@xxxxxxxxxxx>
> + * Roger Quadros <rogerq@xxxxxx>
> + *
> + *
> + */
> +#include <linux/kernel.h>
> +#include <linux/interrupt.h>
> +#include <linux/delay.h>
> +#include <linux/usb/otg.h>
> +
> +#include "gadget.h"
> +#include "drd.h"
> +#include "core.h"
> +
> +/**
> + * cdns3_set_mode - change mode of OTG Core
> + * @cdns: pointer to context structure
> + * @mode: selected mode from cdns_role
> + *
> + * Returns 0 on success otherwise negative errno
> + */
> +int cdns3_set_mode(struct cdns3 *cdns, enum usb_dr_mode mode)
> +{
> + int ret = 0;
> + u32 reg;
> +
> + cdns->current_dr_mode = mode;
> +
> + switch (mode) {
> + case USB_DR_MODE_PERIPHERAL:
> + break;
> + case USB_DR_MODE_HOST:
> + break;
> + case USB_DR_MODE_OTG:
> + dev_dbg(cdns->dev, "Set controller to OTG mode\n");
> + if (cdns->version == CDNS3_CONTROLLER_V1) {
> + reg = readl(&cdns->otg_v1_regs->override);
> + reg |= OVERRIDE_IDPULLUP;
> + writel(reg, &cdns->otg_v1_regs->override);
> + } else {
> + reg = readl(&cdns->otg_v0_regs->ctrl1);
> + reg |= OVERRIDE_IDPULLUP_V0;
> + writel(reg, &cdns->otg_v0_regs->ctrl1);
> + }
> +
> + /*
> + * Hardware specification says: "ID_VALUE must be valid within
> + * 50ms after idpullup is set to '1" so driver must wait
> + * 50ms before reading this pin.
> + */
> + usleep_range(50000, 60000);
> + break;
> + default:
> + cdns->current_dr_mode = USB_DR_MODE_UNKNOWN;
> + dev_err(cdns->dev, "Unsupported mode of operation %d\n", mode);
> + return -EINVAL;
> + }
> +
> + return ret;
> +}
> +
> +int cdns3_get_id(struct cdns3 *cdns)
> +{
> + int id;
> +
> + id = readl(&cdns->otg_regs->sts) & OTGSTS_ID_VALUE;
> + dev_dbg(cdns->dev, "OTG ID: %d", id);
> +
> + return id;
> +}
> +
> +int cdns3_get_vbus(struct cdns3 *cdns)
> +{
> + int vbus;
> +
> + vbus = !!(readl(&cdns->otg_regs->sts) & OTGSTS_VBUS_VALID);
> + dev_dbg(cdns->dev, "OTG VBUS: %d", vbus);
> + return vbus;
> +}
> +
> +int cdns3_is_host(struct cdns3 *cdns)
> +{
> + if (cdns->current_dr_mode == USB_DR_MODE_HOST)
> + return 1;
> + else if (!cdns3_get_id(cdns))
> + return 1;
> +
> + return 0;
> +}
> +
> +int cdns3_is_device(struct cdns3 *cdns)
> +{
> + if (cdns->current_dr_mode == USB_DR_MODE_PERIPHERAL)
> + return 1;
> + else if (cdns->current_dr_mode == USB_DR_MODE_OTG)
> + if (cdns3_get_id(cdns))
> + return 1;
> +
> + return 0;
> +}
> +
> +/**
> + * cdns3_otg_disable_irq - Disable all OTG interrupts
> + * @cdns: Pointer to controller context structure
> + */
> +static void cdns3_otg_disable_irq(struct cdns3 *cdns)
> +{
> + writel(0, &cdns->otg_regs->ien);
> +}
> +
> +/**
> + * cdns3_otg_enable_irq - enable id and sess_valid interrupts
> + * @cdns: Pointer to controller context structure
> + */
> +static void cdns3_otg_enable_irq(struct cdns3 *cdns)
> +{
> + writel(OTGIEN_ID_CHANGE_INT | OTGIEN_VBUSVALID_RISE_INT |
> + OTGIEN_VBUSVALID_FALL_INT, &cdns->otg_regs->ien);
> +}
> +
> +/**
> + * cdns3_drd_switch_host - start/stop host
> + * @cdns: Pointer to controller context structure
> + * @on: 1 for start, 0 for stop
> + *
> + * Returns 0 on success otherwise negative errno
> + */
> +int cdns3_drd_switch_host(struct cdns3 *cdns, int on)
> +{
> + int ret;
> + u32 reg = OTGCMD_OTG_DIS;
> +
> + /* switch OTG core */
> + if (on) {
> + writel(OTGCMD_HOST_BUS_REQ | reg, &cdns->otg_regs->cmd);
> +
> + dev_dbg(cdns->dev, "Waiting till Host mode is turned on\n");
> + ret = cdns3_handshake(&cdns->otg_regs->sts, OTGSTS_XHCI_READY,
> + OTGSTS_XHCI_READY, 100000);
> +
> + if (ret) {
> + dev_err(cdns->dev, "timeout waiting for xhci_ready\n");
> + return ret;
> + }
> + } else {
> + writel(OTGCMD_HOST_BUS_DROP | OTGCMD_DEV_BUS_DROP |
> + OTGCMD_DEV_POWER_OFF | OTGCMD_HOST_POWER_OFF,
> + &cdns->otg_regs->cmd);
> + /* Waiting till H_IDLE state.*/
> + cdns3_handshake(&cdns->otg_regs->state,
> + OTGSTATE_HOST_STATE_MASK,
> + 0, 2000000);
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * cdns3_drd_switch_gadget - start/stop gadget
> + * @cdns: Pointer to controller context structure
> + * @on: 1 for start, 0 for stop
> + *
> + * Returns 0 on success otherwise negative errno
> + */
> +int cdns3_drd_switch_gadget(struct cdns3 *cdns, int on)
> +{
> + int ret;
> + u32 reg = OTGCMD_OTG_DIS;
> +
> + /* switch OTG core */
> + if (on) {
> + writel(OTGCMD_DEV_BUS_REQ | reg, &cdns->otg_regs->cmd);
> +
> + dev_dbg(cdns->dev, "Waiting till Device mode is turned on\n");
> +
> + ret = cdns3_handshake(&cdns->otg_regs->sts, OTGSTS_DEV_READY,
> + OTGSTS_DEV_READY, 100000);
> +
> + if (ret) {
> + dev_err(cdns->dev, "timeout waiting for dev_ready\n");
> + return ret;
> + }
> + } else {
> + /*
> + * driver should wait at least 10us after disabling Device
> + * before turning-off Device (DEV_BUS_DROP)
> + */
> + usleep_range(20, 30);
> + writel(OTGCMD_HOST_BUS_DROP | OTGCMD_DEV_BUS_DROP |
> + OTGCMD_DEV_POWER_OFF | OTGCMD_HOST_POWER_OFF,
> + &cdns->otg_regs->cmd);
> + /* Waiting till DEV_IDLE state.*/
> + cdns3_handshake(&cdns->otg_regs->state, OTGSTATE_DEV_STATE_MASK,
> + 0, 2000000);
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * cdns3_init_otg_mode - initialize drd controller
> + * @cdns: Pointer to controller context structure
> + *
> + * Returns 0 on success otherwise negative errno
> + */
> +static int cdns3_init_otg_mode(struct cdns3 *cdns)
> +{
> + int ret = 0;
> +
> + cdns3_otg_disable_irq(cdns);
> + /* clear all interrupts */
> + writel(~0, &cdns->otg_regs->ivect);
> +
> + ret = cdns3_set_mode(cdns, USB_DR_MODE_OTG);
> + if (ret)
> + return ret;
> +
> + cdns3_otg_enable_irq(cdns);
> + return ret;
> +}
> +
> +/**
> + * cdns3_drd_update_mode - initialize mode of operation
> + * @cdns: Pointer to controller context structure
> + *
> + * Returns 0 on success otherwise negative errno
> + */
> +int cdns3_drd_update_mode(struct cdns3 *cdns)
> +{
> + int ret = 0;
> +
> + if (cdns->desired_dr_mode == cdns->current_dr_mode)
> + return ret;
> +
> + switch (cdns->desired_dr_mode) {
> + case USB_DR_MODE_PERIPHERAL:
> + ret = cdns3_set_mode(cdns, USB_DR_MODE_PERIPHERAL);
> + break;
> + case USB_DR_MODE_HOST:
> + ret = cdns3_set_mode(cdns, USB_DR_MODE_HOST);
> + break;
> + case USB_DR_MODE_OTG:
> + ret = cdns3_init_otg_mode(cdns);
> + break;
> + default:
> + dev_err(cdns->dev, "Unsupported mode of operation %d\n",
> + cdns->dr_mode);
> + return -EINVAL;
> + }
> +
> + return ret;
> +}
> +
> +/**
> + * cdns3_drd_irq - interrupt handler for OTG events
> + *
> + * @irq: irq number for cdns3 core device
> + * @data: structure of cdns3
> + *
> + * Returns IRQ_HANDLED or IRQ_NONE
> + */
> +static irqreturn_t cdns3_drd_irq(int irq, void *data)
> +{
> + irqreturn_t ret = IRQ_NONE;
> + struct cdns3 *cdns = data;
> + u32 reg;
> +
> + if (cdns->dr_mode != USB_DR_MODE_OTG)
> + return ret;
> +
> + reg = readl(&cdns->otg_regs->ivect);
> +
> + if (!reg)
> + return ret;
> +
> + if (reg & OTGIEN_ID_CHANGE_INT) {
> + dev_dbg(cdns->dev, "OTG IRQ: new ID: %d\n",
> + cdns3_get_id(cdns));
> +
> + ret = IRQ_HANDLED;
> + }
> +
> + if (reg & (OTGIEN_VBUSVALID_RISE_INT | OTGIEN_VBUSVALID_FALL_INT)) {
> + dev_dbg(cdns->dev, "OTG IRQ: new VBUS: %d\n",
> + cdns3_get_vbus(cdns));
> +
> + ret = IRQ_HANDLED;
> + }
> +
> + if (ret == IRQ_HANDLED)
> + queue_work(system_freezable_wq, &cdns->role_switch_wq);
> +
> + writel(~0, &cdns->otg_regs->ivect);
> + return ret;
> +}

seems like you could use threaded irq to avoid this workqueue.

> +int cdns3_drd_init(struct cdns3 *cdns)
> +{
> + void __iomem *regs;
> + int ret = 0;
> + u32 state;
> +
> + regs = devm_ioremap_resource(cdns->dev, &cdns->otg_res);
> + if (IS_ERR(regs))
> + return PTR_ERR(regs);
> +
> + /* Detection of DRD version. Controller has been released
> + * in two versions. Both are similar, but they have same changes
> + * in register maps.
> + * The first register in old version is command register and it's read
> + * only, so driver should read 0 from it. On the other hand, in v1
> + * the first register contains device ID number which is not set to 0.
> + * Driver uses this fact to detect the proper version of
> + * controller.
> + */
> + cdns->otg_v0_regs = regs;
> + if (!readl(&cdns->otg_v0_regs->cmd)) {
> + cdns->version = CDNS3_CONTROLLER_V0;
> + cdns->otg_v1_regs = NULL;
> + cdns->otg_regs = regs;
> + writel(1, &cdns->otg_v0_regs->simulate);
> + dev_info(cdns->dev, "DRD version v0 (%08x)\n",
> + readl(&cdns->otg_v0_regs->version));
> + } else {
> + cdns->otg_v0_regs = NULL;
> + cdns->otg_v1_regs = regs;
> + cdns->otg_regs = (void *)&cdns->otg_v1_regs->cmd;
> + cdns->version = CDNS3_CONTROLLER_V1;
> + writel(1, &cdns->otg_v1_regs->simulate);
> + dev_info(cdns->dev, "DRD version v1 (ID: %08x, rev: %08x)\n",
> + readl(&cdns->otg_v1_regs->did),
> + readl(&cdns->otg_v1_regs->rid));
> + }
> +
> + state = OTGSTS_STRAP(readl(&cdns->otg_regs->sts));
> +
> + /* Update dr_mode according to STRAP configuration. */
> + cdns->dr_mode = USB_DR_MODE_OTG;
> + if (state == OTGSTS_STRAP_HOST) {
> + dev_dbg(cdns->dev, "Controller strapped to HOST\n");
> + cdns->dr_mode = USB_DR_MODE_HOST;
> + } else if (state == OTGSTS_STRAP_GADGET) {
> + dev_dbg(cdns->dev, "Controller strapped to PERIPHERAL\n");
> + cdns->dr_mode = USB_DR_MODE_PERIPHERAL;
> + }
> +
> + cdns->desired_dr_mode = cdns->dr_mode;
> + cdns->current_dr_mode = USB_DR_MODE_UNKNOWN;
> +
> + ret = devm_request_threaded_irq(cdns->dev, cdns->otg_irq,
> + cdns3_drd_irq,
> + NULL, IRQF_SHARED,

if you don't have a threaded handler, you should set IRQF_ONESHOT. I
would prefer if you implement a threaded handler that doesn't require
IRQF_ONESHOT, though.

> + dev_name(cdns->dev), cdns);
> +
> + if (ret) {
> + dev_err(cdns->dev, "couldn't get otg_irq\n");
> + return ret;
> + }
> +
> + state = readl(&cdns->otg_regs->sts);
> + if (OTGSTS_OTG_NRDY(state) != 0) {
> + dev_err(cdns->dev, "Cadence USB3 OTG device not ready\n");
> + return -ENODEV;
> + }
> +
> + return ret;
> +}
> +
> +int cdns3_drd_exit(struct cdns3 *cdns)
> +{
> + return 0;
> +}
> diff --git a/drivers/usb/cdns3/drd.h b/drivers/usb/cdns3/drd.h
> new file mode 100644
> index 000000000000..bf6c7bc41b58
> --- /dev/null
> +++ b/drivers/usb/cdns3/drd.h
> @@ -0,0 +1,166 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Cadence USB3 DRD header file.
> + *
> + * Copyright (C) 2018-2019 Cadence.
> + *
> + * Author: Pawel Laszczak <pawell@xxxxxxxxxxx>
> + */
> +#ifndef __LINUX_CDNS3_DRD
> +#define __LINUX_CDNS3_DRD
> +
> +#include <linux/usb/otg.h>
> +#include <linux/phy/phy.h>
> +#include "core.h"
> +
> +/* DRD register interface for version v1. */
> +struct cdns3_otg_regs {
> + __le32 did;
> + __le32 rid;
> + __le32 capabilities;
> + __le32 reserved1;
> + __le32 cmd;
> + __le32 sts;
> + __le32 state;
> + __le32 reserved2;
> + __le32 ien;
> + __le32 ivect;
> + __le32 refclk;
> + __le32 tmr;
> + __le32 reserved3[4];
> + __le32 simulate;
> + __le32 override;
> + __le32 susp_ctrl;
> + __le32 reserved4;
> + __le32 anasts;
> + __le32 adp_ramp_time;
> + __le32 ctrl1;
> + __le32 ctrl2;
> +};
> +
> +/* DRD register interface for version v0. */
> +struct cdns3_otg_legacy_regs {
> + __le32 cmd;
> + __le32 sts;
> + __le32 state;
> + __le32 refclk;
> + __le32 ien;
> + __le32 ivect;
> + __le32 reserved1[3];
> + __le32 tmr;
> + __le32 reserved2[2];
> + __le32 version;
> + __le32 capabilities;
> + __le32 reserved3[2];
> + __le32 simulate;
> + __le32 reserved4[5];
> + __le32 ctrl1;
> +};
> +
> +/*
> + * Common registers interface for both version of DRD.
> + */
> +struct cdns3_otg_common_regs {
> + __le32 cmd;
> + __le32 sts;
> + __le32 state;
> + __le32 different1;
> + __le32 ien;
> + __le32 ivect;
> +};
> +
> +/* CDNS_RID - bitmasks */
> +#define CDNS_RID(p) ((p) & GENMASK(15, 0))
> +
> +/* CDNS_VID - bitmasks */
> +#define CDNS_DID(p) ((p) & GENMASK(31, 0))
> +
> +/* OTGCMD - bitmasks */
> +/* "Request the bus for Device mode. */
> +#define OTGCMD_DEV_BUS_REQ BIT(0)
> +/* Request the bus for Host mode */
> +#define OTGCMD_HOST_BUS_REQ BIT(1)
> +/* Enable OTG mode. */
> +#define OTGCMD_OTG_EN BIT(2)
> +/* Disable OTG mode */
> +#define OTGCMD_OTG_DIS BIT(3)
> +/*"Configure OTG as A-Device. */
> +#define OTGCMD_A_DEV_EN BIT(4)
> +/*"Configure OTG as A-Device. */
> +#define OTGCMD_A_DEV_DIS BIT(5)
> +/* Drop the bus for Device mod e. */
> +#define OTGCMD_DEV_BUS_DROP BIT(8)
> +/* Drop the bus for Host mode*/
> +#define OTGCMD_HOST_BUS_DROP BIT(9)
> +/* Power Down USBSS-DEV. */
> +#define OTGCMD_DEV_POWER_OFF BIT(11)
> +/* Power Down CDNSXHCI. */
> +#define OTGCMD_HOST_POWER_OFF BIT(12)
> +
> +/* OTGIEN - bitmasks */
> +/* ID change interrupt enable */
> +#define OTGIEN_ID_CHANGE_INT BIT(0)
> +/* Vbusvalid fall detected interrupt enable.*/
> +#define OTGIEN_VBUSVALID_RISE_INT BIT(4)
> +/* Vbusvalid fall detected interrupt enable */
> +#define OTGIEN_VBUSVALID_FALL_INT BIT(5)
> +
> +/* OTGSTS - bitmasks */
> +/*
> + * Current value of the ID pin. It is only valid when idpullup in
> + * OTGCTRL1_TYPE register is set to '1'.
> + */
> +#define OTGSTS_ID_VALUE BIT(0)
> +/* Current value of the vbus_valid */
> +#define OTGSTS_VBUS_VALID BIT(1)
> +/* Current value of the b_sess_vld */
> +#define OTGSTS_SESSION_VALID BIT(2)
> +/*Device mode is active*/
> +#define OTGSTS_DEV_ACTIVE BIT(3)
> +/* Host mode is active. */
> +#define OTGSTS_HOST_ACTIVE BIT(4)
> +/* OTG Controller not ready. */
> +#define OTGSTS_OTG_NRDY_MASK BIT(11)
> +#define OTGSTS_OTG_NRDY(p) ((p) & OTGSTS_OTG_NRDY_MASK)
> +/*
> + * Value of the strap pins.
> + * 000 - no default configuration
> + * 010 - Controller initiall configured as Host
> + * 100 - Controller initially configured as Device
> + */
> +#define OTGSTS_STRAP(p) (((p) & GENMASK(14, 12)) >> 12)
> +#define OTGSTS_STRAP_NO_DEFAULT_CFG 0x00
> +#define OTGSTS_STRAP_HOST_OTG 0x01
> +#define OTGSTS_STRAP_HOST 0x02
> +#define OTGSTS_STRAP_GADGET 0x04
> +/* Host mode is turned on. */
> +#define OTGSTS_XHCI_READY BIT(26)
> +/* "Device mode is turned on .*/
> +#define OTGSTS_DEV_READY BIT(27)
> +
> +/* OTGSTATE- bitmasks */
> +#define OTGSTATE_DEV_STATE_MASK GENMASK(2, 0)
> +#define OTGSTATE_HOST_STATE_MASK GENMASK(5, 3)
> +#define OTGSTATE_HOST_STATE_IDLE 0x0
> +#define OTGSTATE_HOST_STATE_VBUS_FALL 0x7
> +#define OTGSTATE_HOST_STATE(p) (((p) & OTGSTATE_HOST_STATE_MASK) >> 3)
> +
> +/* OTGREFCLK - bitmasks */
> +#define OTGREFCLK_STB_CLK_SWITCH_EN BIT(31)
> +
> +/* OVERRIDE - bitmasks */
> +#define OVERRIDE_IDPULLUP BIT(0)
> +/* Only for CDNS3_CONTROLLER_V0 version */
> +#define OVERRIDE_IDPULLUP_V0 BIT(24)
> +
> +int cdns3_is_host(struct cdns3 *cdns);
> +int cdns3_is_device(struct cdns3 *cdns);
> +int cdns3_get_id(struct cdns3 *cdns);
> +int cdns3_get_vbus(struct cdns3 *cdns);
> +int cdns3_drd_init(struct cdns3 *cdns);
> +int cdns3_drd_exit(struct cdns3 *cdns);
> +int cdns3_drd_update_mode(struct cdns3 *cdns);
> +int cdns3_drd_switch_gadget(struct cdns3 *cdns, int on);
> +int cdns3_drd_switch_host(struct cdns3 *cdns, int on);
> +
> +#endif /* __LINUX_CDNS3_DRD */
> diff --git a/drivers/usb/cdns3/ep0.c b/drivers/usb/cdns3/ep0.c
> new file mode 100644
> index 000000000000..6fa711ead6d0
> --- /dev/null
> +++ b/drivers/usb/cdns3/ep0.c
> @@ -0,0 +1,920 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Cadence USBSS DRD Driver - gadget side.
> + *
> + * Copyright (C) 2018 Cadence Design Systems.
> + * Copyright (C) 2017-2018 NXP
> + *
> + * Authors: Pawel Jez <pjez@xxxxxxxxxxx>,
> + * Pawel Laszczak <pawell@xxxxxxxxxxx>
> + * Peter Chen <peter.chen@xxxxxxx>
> + */
> +
> +#include <linux/usb/composite.h>
> +
> +#include "gadget.h"
> +#include "trace.h"
> +
> +static struct usb_endpoint_descriptor cdns3_gadget_ep0_desc = {
> + .bLength = USB_DT_ENDPOINT_SIZE,
> + .bDescriptorType = USB_DT_ENDPOINT,
> + .bmAttributes = USB_ENDPOINT_XFER_CONTROL,
> +};
> +
> +/**
> + * cdns3_ep0_run_transfer - Do transfer on default endpoint hardware
> + * @priv_dev: extended gadget object
> + * @dma_addr: physical address where data is/will be stored
> + * @length: data length
> + * @erdy: set it to 1 when ERDY packet should be sent -
> + * exit from flow control state
> + */
> +static void cdns3_ep0_run_transfer(struct cdns3_device *priv_dev,
> + dma_addr_t dma_addr,
> + unsigned int length, int erdy, int zlp)
> +{
> + struct cdns3_usb_regs __iomem *regs = priv_dev->regs;
> + struct cdns3_endpoint *priv_ep = priv_dev->eps[0];
> +
> + priv_ep->trb_pool[0].buffer = TRB_BUFFER(dma_addr);
> + priv_ep->trb_pool[0].length = TRB_LEN(length);
> +
> + if (zlp) {
> + priv_ep->trb_pool[0].control = TRB_CYCLE | TRB_TYPE(TRB_NORMAL);
> + priv_ep->trb_pool[1].buffer = TRB_BUFFER(dma_addr);
> + priv_ep->trb_pool[1].length = TRB_LEN(0);
> + priv_ep->trb_pool[1].control = TRB_CYCLE | TRB_IOC |
> + TRB_TYPE(TRB_NORMAL);
> + } else {
> + priv_ep->trb_pool[0].control = TRB_CYCLE | TRB_IOC |
> + TRB_TYPE(TRB_NORMAL);
> + priv_ep->trb_pool[1].control = 0;
> + }
> +
> + trace_cdns3_prepare_trb(priv_ep, priv_ep->trb_pool);
> +
> + cdns3_select_ep(priv_dev, priv_dev->ep0_data_dir);
> +
> + writel(EP_STS_TRBERR, &regs->ep_sts);
> + writel(EP_TRADDR_TRADDR(priv_ep->trb_pool_dma), &regs->ep_traddr);
> + trace_cdns3_doorbell_ep0(priv_dev->ep0_data_dir ? "ep0in" : "ep0out",
> + readl(&regs->ep_traddr));
> +
> + /* TRB should be prepared before starting transfer. */
> + writel(EP_CMD_DRDY, &regs->ep_cmd);
> +
> + /* Resume controller before arming transfer. */
> + __cdns3_gadget_wakeup(priv_dev);
> +
> + if (erdy)
> + writel(EP_CMD_ERDY, &priv_dev->regs->ep_cmd);
> +}
> +
> +/**
> + * cdns3_ep0_delegate_req - Returns status of handling setup packet
> + * Setup is handled by gadget driver
> + * @priv_dev: extended gadget object
> + * @ctrl_req: pointer to received setup packet
> + *
> + * Returns zero on success or negative value on failure
> + */
> +static int cdns3_ep0_delegate_req(struct cdns3_device *priv_dev,
> + struct usb_ctrlrequest *ctrl_req)
> +{
> + int ret;
> +
> + spin_unlock(&priv_dev->lock);
> + priv_dev->setup_pending = 1;
> + ret = priv_dev->gadget_driver->setup(&priv_dev->gadget, ctrl_req);
> + priv_dev->setup_pending = 0;
> + spin_lock(&priv_dev->lock);
> + return ret;
> +}
> +
> +static void cdns3_prepare_setup_packet(struct cdns3_device *priv_dev)
> +{
> + priv_dev->ep0_data_dir = 0;
> + priv_dev->ep0_stage = CDNS3_SETUP_STAGE;
> + cdns3_ep0_run_transfer(priv_dev, priv_dev->setup_dma,
> + sizeof(struct usb_ctrlrequest), 0, 0);
> +}
> +
> +static void cdns3_ep0_complete_setup(struct cdns3_device *priv_dev,
> + u8 send_stall, u8 send_erdy)
> +{
> + struct cdns3_endpoint *priv_ep = priv_dev->eps[0];
> + struct usb_request *request;
> +
> + request = cdns3_next_request(&priv_ep->pending_req_list);
> + if (request)
> + list_del_init(&request->list);
> +
> + if (send_stall) {
> + cdns3_dbg(priv_ep->cdns3_dev, "STALL for ep0\n");
> + /* set_stall on ep0 */
> + cdns3_select_ep(priv_dev, 0x00);
> + writel(EP_CMD_SSTALL, &priv_dev->regs->ep_cmd);
> + } else {
> + cdns3_prepare_setup_packet(priv_dev);
> + }
> +
> + priv_dev->ep0_stage = CDNS3_SETUP_STAGE;
> + writel((send_erdy ? EP_CMD_ERDY : 0) | EP_CMD_REQ_CMPL,
> + &priv_dev->regs->ep_cmd);
> +
> + cdns3_allow_enable_l1(priv_dev, 1);
> +}
> +
> +/**
> + * cdns3_req_ep0_set_configuration - Handling of SET_CONFIG standard USB request
> + * @priv_dev: extended gadget object
> + * @ctrl_req: pointer to received setup packet
> + *
> + * Returns 0 if success, USB_GADGET_DELAYED_STATUS on deferred status stage,
> + * error code on error
> + */
> +static int cdns3_req_ep0_set_configuration(struct cdns3_device *priv_dev,
> + struct usb_ctrlrequest *ctrl_req)
> +{
> + enum usb_device_state device_state = priv_dev->gadget.state;
> + struct cdns3_endpoint *priv_ep;
> + u32 config = le16_to_cpu(ctrl_req->wValue);
> + int result = 0;
> + int i;
> +
> + switch (device_state) {
> + case USB_STATE_ADDRESS:
> + /* Configure non-control EPs */
> + for (i = 0; i < CDNS3_ENDPOINTS_MAX_COUNT; i++) {
> + priv_ep = priv_dev->eps[i];
> + if (!priv_ep)
> + continue;
> +
> + if (priv_ep->flags & EP_CLAIMED)
> + cdns3_ep_config(priv_ep);
> + }
> +
> + result = cdns3_ep0_delegate_req(priv_dev, ctrl_req);
> +
> + if (result)
> + return result;
> +
> + if (config) {
> + cdns3_set_hw_configuration(priv_dev);
> + } else {
> + cdns3_hw_reset_eps_config(priv_dev);
> + usb_gadget_set_state(&priv_dev->gadget,
> + USB_STATE_ADDRESS);
> + }
> + break;
> + case USB_STATE_CONFIGURED:
> + result = cdns3_ep0_delegate_req(priv_dev, ctrl_req);
> +
> + if (!config && !result) {
> + cdns3_hw_reset_eps_config(priv_dev);
> + usb_gadget_set_state(&priv_dev->gadget,
> + USB_STATE_ADDRESS);
> + }
> + break;
> + default:
> + result = -EINVAL;
> + }
> +
> + return result;
> +}
> +
> +/**
> + * cdns3_req_ep0_set_address - Handling of SET_ADDRESS standard USB request
> + * @priv_dev: extended gadget object
> + * @ctrl_req: pointer to received setup packet
> + *
> + * Returns 0 if success, error code on error
> + */
> +static int cdns3_req_ep0_set_address(struct cdns3_device *priv_dev,
> + struct usb_ctrlrequest *ctrl_req)
> +{
> + enum usb_device_state device_state = priv_dev->gadget.state;
> + u32 reg;
> + u32 addr;
> +
> + addr = le16_to_cpu(ctrl_req->wValue);
> +
> + if (addr > USB_DEVICE_MAX_ADDRESS) {
> + dev_err(priv_dev->dev,
> + "Device address (%d) cannot be greater than %d\n",
> + addr, USB_DEVICE_MAX_ADDRESS);
> + return -EINVAL;
> + }
> +
> + if (device_state == USB_STATE_CONFIGURED) {
> + dev_err(priv_dev->dev,
> + "can't set_address from configured state\n");
> + return -EINVAL;
> + }
> +
> + reg = readl(&priv_dev->regs->usb_cmd);
> +
> + writel(reg | USB_CMD_FADDR(addr) | USB_CMD_SET_ADDR,
> + &priv_dev->regs->usb_cmd);
> +
> + usb_gadget_set_state(&priv_dev->gadget,
> + (addr ? USB_STATE_ADDRESS : USB_STATE_DEFAULT));
> +
> + return 0;
> +}
> +
> +/**
> + * cdns3_req_ep0_get_status - Handling of GET_STATUS standard USB request
> + * @priv_dev: extended gadget object
> + * @ctrl_req: pointer to received setup packet
> + *
> + * Returns 0 if success, error code on error
> + */
> +static int cdns3_req_ep0_get_status(struct cdns3_device *priv_dev,
> + struct usb_ctrlrequest *ctrl)
> +{
> + __le16 *response_pkt;
> + u16 usb_status = 0;
> + u32 recip;
> + u32 reg;
> +
> + recip = ctrl->bRequestType & USB_RECIP_MASK;
> +
> + switch (recip) {
> + case USB_RECIP_DEVICE:
> + /* self powered */
> + if (priv_dev->is_selfpowered)
> + usb_status = BIT(USB_DEVICE_SELF_POWERED);
> +
> + if (priv_dev->wake_up_flag)
> + usb_status |= BIT(USB_DEVICE_REMOTE_WAKEUP);
> +
> + if (priv_dev->gadget.speed != USB_SPEED_SUPER)
> + break;
> +
> + reg = readl(&priv_dev->regs->usb_sts);
> +
> + if (priv_dev->u1_allowed)
> + usb_status |= BIT(USB_DEV_STAT_U1_ENABLED);
> +
> + if (priv_dev->u2_allowed)
> + usb_status |= BIT(USB_DEV_STAT_U2_ENABLED);
> +
> + break;
> + case USB_RECIP_INTERFACE:
> + return cdns3_ep0_delegate_req(priv_dev, ctrl);
> + case USB_RECIP_ENDPOINT:
> + /* check if endpoint is stalled */
> + cdns3_select_ep(priv_dev, ctrl->wIndex);
> + if (EP_STS_STALL(readl(&priv_dev->regs->ep_sts)))
> + usb_status = BIT(USB_ENDPOINT_HALT);
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + response_pkt = (__le16 *)priv_dev->setup_buf;
> + *response_pkt = cpu_to_le16(usb_status);
> +
> + cdns3_ep0_run_transfer(priv_dev, priv_dev->setup_dma,
> + sizeof(*response_pkt), 1, 0);
> + return 0;
> +}
> +
> +static int cdns3_ep0_feature_handle_device(struct cdns3_device *priv_dev,
> + struct usb_ctrlrequest *ctrl,
> + int set)
> +{
> + enum usb_device_state state;
> + enum usb_device_speed speed;
> + int ret = 0;
> + u32 wValue;
> + u32 wIndex;
> + u16 tmode;
> +
> + wValue = le16_to_cpu(ctrl->wValue);
> + wIndex = le16_to_cpu(ctrl->wIndex);
> + state = priv_dev->gadget.state;
> + speed = priv_dev->gadget.speed;
> +
> + switch (ctrl->wValue) {
> + case USB_DEVICE_REMOTE_WAKEUP:
> + priv_dev->wake_up_flag = !!set;
> + break;
> + case USB_DEVICE_U1_ENABLE:
> + if (state != USB_STATE_CONFIGURED || speed != USB_SPEED_SUPER)
> + return -EINVAL;
> +
> + priv_dev->u1_allowed = !!set;
> + break;
> + case USB_DEVICE_U2_ENABLE:
> + if (state != USB_STATE_CONFIGURED || speed != USB_SPEED_SUPER)
> + return -EINVAL;
> +
> + priv_dev->u2_allowed = !!set;
> + break;
> + case USB_DEVICE_LTM_ENABLE:
> + ret = -EINVAL;
> + break;
> + case USB_DEVICE_TEST_MODE:
> + if (state != USB_STATE_CONFIGURED || speed > USB_SPEED_HIGH)
> + return -EINVAL;
> +
> + tmode = le16_to_cpu(ctrl->wIndex);
> +
> + if (!set || (tmode & 0xff) != 0)
> + return -EINVAL;
> +
> + switch (tmode >> 8) {
> + case TEST_J:
> + case TEST_K:
> + case TEST_SE0_NAK:
> + case TEST_PACKET:
> + cdns3_ep0_complete_setup(priv_dev, 0, 1);
> + /**
> + * Little delay to give the controller some time
> + * for sending status stage.
> + * This time should be less then 3ms.
> + */
> + usleep_range(1000, 2000);
> + cdns3_set_register_bit(&priv_dev->regs->usb_cmd,
> + USB_CMD_STMODE |
> + USB_STS_TMODE_SEL(tmode - 1));

I could bet this doesn't work. You're entering test mode before status
stage. Make sure to run your driver against USB CV chapter 9 tests. You
can use g_zero for testing.

> + break;
> + default:
> + ret = -EINVAL;
> + }
> + break;
> + default:
> + ret = -EINVAL;
> + }
> +
> + return ret;
> +}
> +
> +static int cdns3_ep0_feature_handle_intf(struct cdns3_device *priv_dev,
> + struct usb_ctrlrequest *ctrl,
> + int set)
> +{
> + u32 wValue;
> + int ret = 0;
> +
> + wValue = le16_to_cpu(ctrl->wValue);
> +
> + switch (wValue) {
> + case USB_INTRF_FUNC_SUSPEND:
> + break;
> + default:
> + ret = -EINVAL;
> + }
> +
> + return ret;
> +}
> +
> +static int cdns3_ep0_feature_handle_endpoint(struct cdns3_device *priv_dev,
> + struct usb_ctrlrequest *ctrl,
> + int set)
> +{
> + struct cdns3_endpoint *priv_ep;
> + int ret = 0;
> + u8 index;
> +
> + if (le16_to_cpu(ctrl->wValue) != USB_ENDPOINT_HALT)
> + return -EINVAL;
> +
> + if (!(ctrl->wIndex & ~USB_DIR_IN))
> + return 0;
> +
> + index = cdns3_ep_addr_to_index(ctrl->wIndex);
> + priv_ep = priv_dev->eps[index];
> +
> + cdns3_select_ep(priv_dev, ctrl->wIndex);
> +
> + if (set) {
> + cdns3_dbg(priv_ep->cdns3_dev, "Stall endpoint %s\n",
> + priv_ep->name);
> + writel(EP_CMD_SSTALL, &priv_dev->regs->ep_cmd);
> + priv_ep->flags |= EP_STALL;
> + } else {
> + struct usb_request *request;
> +
> + if (priv_dev->eps[index]->flags & EP_WEDGE) {
> + cdns3_select_ep(priv_dev, 0x00);
> + return 0;
> + }
> +
> + cdns3_dbg(priv_ep->cdns3_dev, "Clear Stalled endpoint %s\n",
> + priv_ep->name);

why do you need your own wrapper around dev_dbg()? This looks quite unnecessary.

I'll stop here and review more at a later moment. Now that I had a look,
this doesn't look ready for prime time yet.

--
balbi